Sinusoidal 50 Hz magnetic fields do not affect structural morphology and proliferation of human cells in vitro

The effects of electromagnetic fields on several processes related to cell physiology and proliferation are currently being investigated. Although the results are still not conclusive and even conflicting, there seems to be a fairly good agreement on the early effects of electromagnetic fields on th e generation of free radicals and on Ca++-intracellular concentration and t ransport. To evaluate the long-lasting consequences of these precocious eve nts, we examined the effects of short- and long-term magnetic field exposur e on structural organization (cytokeratin or actin detection), proliferatio n (bromodeoxyuridine incorporation and propidium iodide staining), colony f orming ability and viability (trypan blue exclusion test) of highly prolife rating MCF-7 cells (from human breast carcinoma) and on slowly proliferatin g normal human fibroblasts (from healthy donors). Cells were exposed to eit her 20 or 500 muT sinusoidally oscillating (50Hz) magnetic fields for diffe rent lengths of time (1 to 4 days). Short (1 day)- and long (4 days)-time e xposure to the two intensities did not affect MCF-7 growth and viability, c olony number and size, or cellular distribution along the cell cycle; neith er were the cell morphology and the intracellular distribution and amount o f cytokeratin modified. Similarly, no modifications in the actin distributi on and proliferative potential were observed in normal human fibroblasts. T hese findings suggest that under our experimental conditions, continuous ex posure to magnetic fields does not result in any appreciable effect in both normal and tumor cells in vitro.